Treatment Responses to Integrase Strand-transfer Inhibitor-containing Antiretroviral Regimens in Combination With Short-course Rifapentine-based Regimens for Latent Tuberculosis Infection Among People With HIV

BACKGROUND

Real-world experience with combinations of short-course rifapentine-based regimens and integrase strand-transfer inhibitor-containing antiretroviral therapy (ART) in management of latent tuberculous infection (LTBI) is limited among people with human immunodeficiency virus (PWH).

METHODS

From August 2019 to October 2022, PWH receiving 3 months of weekly rifapentine plus isoniazid (3HP) or 1 month of daily rifapentine plus isoniazid (1HP) in combination with ART were included. The primary outcome was virologic response within 12 months after LTBI treatment; secondary outcomes included treatment completion rate and safety of LTBI regimens.

RESULTS

During the study period, 479 PWH (94.6% male; median age, 43 years) were included: 142 received 1HP and bictegravir (BIC)-containing regimens (1HP/BIC group), 46 1HP and dolutegravir (DTG)-containing regimens (1HP/DTG group), 38 3HP and BIC-containing regimens (3HP/BIC group), 214 3HP and DTG-containing regimens (3HP/DTG group), 17 1HP and other ART regimens (1HP/others group), and 22 3HP/other ART regimens (3HP/others group). In the intention-to-treat analysis, the proportions of PWH maintaining plasma HIV-1 RNA <200 copies/mL within 12 months after LTBI treatment completion were 96.5% (1HP/BIC), 100% (1HP/DTG), 100% (3HP/BIC), 95.8% (3HP/DTG), 100% (1HP/others), and 100% (3HP/others). The overall completion rates were >80% for all treatment groups, whereas >50% of the included PWH experienced any adverse event. LTBI regimens and ART combinations were not associated with virologic response and completion rate.

CONCLUSIONS

Combinations of short-course rifapentine-based regimens and integrase strand-transfer inhibitor-containing ART maintained viral suppression for most PWH within 12 months of LTBI treatment completion with low rates of grade 3 or higher adverse events.

Incidence and risk factors of active tuberculosis among older individuals with latent tuberculosis infection: a cohort study in two high-epidemic sites in eastern China

Background

The influencing factors of the process from latent tuberculosis infection (LTBI) to the onset of active tuberculosis (TB) remain unknown among different population groups, especially among older individuals in high-incidence areas. This study aimed to investigate the development of active TB among older adults with LTBI and identify groups in greatest need of improved prevention and control strategies for TB.

Methods

In 2021, we implemented an investigation among older individuals (≥ 65 years old) in two towns in Zhejiang Province with the highest incidence of TB. All participants underwent assessment using standardized questionnaires, physical examinations, interferon-gamma release assays, and chest radiography. All the participants with suspected TB based on the clinical symptoms or abnormal chest radiography results, as well as those with LTBI, were referred for diagnostic investigation in accordance with the national guidelines. Those with an initial diagnosis of TB were then excluded, whereas those with LTBI were included in a follow-up at baseline. Incident patients with active TB were identified from the Chinese Tuberculosis Management Information System, and a multivariate Cox regression model was used to estimate the incidence and risk of TB among those with LTBI.

Results

In total, 667 participants with LTBI were followed up for 1,315.3 person-years, revealing a disease density of 1,292.5 individuals/100,000 person-years (17/1,315.3). For those with LTBI, chest radiograph abnormalities had adjusted hazard ratios for active TB of 4.9 (1.6-15.3).

Conclusions

The presence of abnormal chest radiography findings increased the risk of active TB among older individuals with LTBI in high-epidemic sites in eastern China.

Interferon-Gamma Release Assay

Reductions in tuberculosis (TB) incidence require identification of individuals at high risk of developing active disease, such as those with recent Mycobacterium tuberculosis (Mtb) infection. Using a prospective household contact (HHC) study in Kampala, Uganda, we diagnosed new Mtb infection using both the tuberculin skin test (TST) and interferon-gamma release assay (IGRA). Our study aimed to determine if the TST adds additional value to the characterization of IGRA converters. We identified 13 HHCs who only converted the IGRA (QFT-only converters), 39 HHCs who only converted their TST (TST-only converters), and 24 HHCs who converted both tests (QFT/TST converters). Univariate analysis revealed that TST-only converters were older. Additionally, increased odds of TST-only conversion were associated with older age (p = 0.02) and crowdedness (p = 0.025). QFT/TST converters had higher QFT quantitative values at conversion than QFT-only converters and a bigger change in TST quantitative values at conversion than TST-only converters. Collectively, these data indicate that TST conversion alone likely overestimates Mtb infection. Its correlation to older age suggests an "environmental" boosting response due to prolonged exposure to environmental mycobacteria. This result also suggests that QFT/TST conversion may be associated with a more robust immune response, which should be considered when planning vaccine studies.

Pulmonary Tuberculosis Incidence among Interferon-Gamma Release Assay-Positive Individuals with Latent Tuberculosis Infection and Fibrotic Lesions in a Vulnerable Urban Population in Osaka City, Japan, 2015-2021

Latent tuberculosis infection (LTBI) with fibrotic lesions (FL) can progress to active tuberculosis (TB). Most previous studies have used tuberculin skin tests, which have lower specificity than interferon-gamma release assays (IGRAs), for LTBI diagnosis. This study evaluated the incidence of active TB among individuals with LTBI (diagnosed using IGRAs) and FL in Nishinari District, Osaka City. In total, 54 men (mean age: 68.7 years) were enrolled, of whom 10 (18.5%) were homeless, and 36 (66.7%) were welfare recipients. The median observation period was 1,084 days (range: 64-2,907 days). The incidence rate of active TB among individuals with LTBI and FL was 1.18 (95% confidence interval: 0.32-4.29) cases per 100 person-years. Among the 19 participants who had not been treated with anti-TB therapy, one (5.3%) progressed to active TB, and among the 30 participants who had completed anti-TB treatment, one (3.3%) progressed to active TB. The other 5 participants did not have TB. This study revealed the incidence of active TB among individuals with LTBI, diagnosed using IGRAs, and FL in a vulnerable urban population. The higher incidence than that reported in previous studies reinforces the importance of improved LTBI management strategies, including chest radiography screening, and LTBI treatment.

Impact of Exposure to Vaccination and Infection on Cellular and Antibody Response to SARS-CoV-2 in CVID Patients Through COVID-19 Pandemic

PURPOSE

The purpose of this study is to investigate the kinetics of response against SARS-CoV-2 elicited by vaccination and/or breakthrough infection (occurred after 3 doses of BNT162b2) in a cohort CVID patients.

METHODS

We measured humoral and cellular immunity using quantitative anti-spike antibody (anti-S-IgG) and neutralization assay and specific interferon-gamma release assay (IGRA) before and after the third or fourth dose of BNT162b2 and/or after COVID-19.

RESULTS

In CVID, 58.3% seroconverted after 2 doses that increased to 77.8% after 3 doses. Between the second and third dose, there was a decline in humoral compartment that led to titers below the cutoff of 1:10 (MNA90%) in CVID. This was paralleled by a significantly lower proportion (30%) and reduced magnitude of the residual cellular response among CVID. The third dose achieved a lower titer of anti-S and nAb against the Wuhan strain than HC and significantly decreased the rate of those showing solely a positive neutralizing activity and those with simultaneous negativity of IGRA and nAbs; the differences in IGRA were overall reduced with respect to HC. At further sampling after breakthrough SARS-COV-2 infection, mostly in the omicron era, or fourth dose, 6 months after the last event, the residual nAb titer to Wuhan strain was still significantly higher in HC, while there was no significant difference of nAbs to BA.1. The rate of IGRA responders was 65.5% in CVID and 90.5% in HC (p=0.04), while the magnitude of response was similar. None of CVID had double negativity to nAbs and IGRA at the last sampling.

CONCLUSION

This data shows an increase of adaptive immunity in CVID after mRNA vaccination in parallel to boosters, accrual number of exposures and formation of hybrid immunity.

Risk of tuberculosis in children with rheumatologic diseases treated with biological agents: A cross-sectional cohort study

Objectives

This study aimed to evaluate the risk of tuberculosis (TB) disease in children receiving biological agents for rheumatologic diseases, focusing on appropriate screening tests in a high-priority country for TB control.

Patients and methods

One hundred nine children (56 females, 53 males; range, 3.4 to 16.2 years) who received any biological agent for rheumatologic diseases for more than two years between May 2012 and October 2021 were included in this retrospective study. Patients were screened for TB infection using tuberculin skin test (TST) or interferon-gamma release assay (IGRA). Following the initial evaluation, patients were clinically examined for TB every three months by a comprehensive medical history and physical examination, and every 12 months using TST or IGRA.

Results

At the initiation of the biological agent, the patients' mean age was 12.4±4.5 years. The average follow-up duration was 3.6±1.3 years (range, 2.6 to 10.2 years) for patients treated with biological agents. Each patient had a documented Bacillus Calmette-Guérin vaccination. Before the initiating of therapy, TST was performed alone in 45 (41.3%) patients and in combination with IGRA in 64 (58.7%) patients. In the 64 patients who underwent both TST and IGRA, IGRA revealed nine (14.1%) positive results. Six (66.7%) of these nine patients, however, had negative baseline TST. Four (7.3%) of the 55 individuals whose initial IGRA results were negative also had positive TST results. Overall, no TB disease was observed after a follow-up period.

Conclusion

This study reveals that biological agents were not associated with an increased risk of TB disease in closely monitored children. Additionally, the concomitant use of TST and IGRA for screening of TB is reasonable in patients receiving biological agents.

Cellular immune response to SARS-CoV-2 in patients with primary antibody deficiencies

Introduction

Primary antibody deficiencies (PAD) are inborn defects of the immune system that result in increased susceptibility to infections. Despite the reduced response to vaccination, PAD patients still benefit from it by reducing the risk of severe infections and complications. SARS-CoV-2 vaccines are recommended in PAD patients, but their immune effects are poorly studied. Here, we analyze virus-specific T-cell responses in PAD patients after booster vaccination against SARS-CoV-2.

Patients and methods

The study included 57 adult PAD patients on long-term immunoglobulin replacement therapy (IgRT) diagnosed with X-linked agammaglobulinemia (XLA; n = 4), common variable immunodeficiency (CVID; n = 33), isotype defects or IgG subclass deficiency (n = 6), and unclassified IgG deficiency (n = 14). Of those, 49 patients (86%) received vaccination against SARS-CoV-2 using mRNA vaccine (Pfizer-BioNTech). T-cell responses were assessed at a median of 21 (13 - 30) weeks after the booster dose (mainly the third dose) using commercially available interferon-gamma release assay (IGRA) with recombinant SARS-CoV-2 spike S1 protein.

Results

Vaccinated PAD patients showed an increased (3.8-fold, p = 0.004) release of IFN-γ upon S1 stimulation. In this group, we also documented higher serum levels of anti-SARS-CoV-2 IgG (4.1-fold, p = 0.01), although they were not associated with IGRA results. Further subgroup analysis revealed very similar IGRA responses in CVID and unclassified IgG deficiencies that were 2.4-fold increased compared to XLA and 5.4-fold increased compared to patients with isotype defects or IgG subclass deficiencies (e.g., vs. CVID: p = 0.016). As expected, CVID and XLA patients showed decreased serum titers of anti-SARS-CoV-2 antibodies compared to other studied groups (e.g., CVID vs. unclassified IgG deficiency: 4.4-fold, p = 0.006). The results did not depend directly on IgRT mode or dose, number of vaccine doses and time from the last booster dose, and clinical manifestations of PAD. Interestingly, anti-SARS-CoV-2 titers were positively correlated with serum immunoglobulin levels before IgRT (e.g., for IgA: r = 0.45, p<0.001; for IgG: r = 0.34, p = 0.009) and the percentage of peripheral blood NK cells (r = 0.48, p<0.001).

Conclusions

Our results documented satisfactory in vitro cellular immune response in PAD patients after booster SARS-CoV-2 vaccination. Therefore, even patients with agammaglobulinemia should benefit from vaccination due to the apparent induction of cell-mediated immunity, which, together with IgRT, grants comprehensive protection against the pathogen.

Evaluation of a New Chemiluminescent Immunoassay-Based Interferon-Gamma Release Assay for Detection of Latent Tuberculosis Infection

Background and Objectives: This study aimed to evaluate the performance of a new chemiluminescent immunoassay-based tuberculosis (TB) interferon-gamma release assay (IGRA), AdvanSureI3 TB-IGRA (LG Chem Ltd., Seoul, Republic of Korea), for detecting latent tuberculosis infection in comparison with T-SPOT.TB (Oxford Immunotec, Oxford, UK). Materials and Methods: Between June 2021 and December 2021, 125 non-duplicate blood specimens were collected from adult volunteers; each subject received both tests concurrently. Total agreement and Cohen's kappa coefficient (κ) were used to calculate concordance. The Jonckheere-Terpstra test was used to examine the correlation between interferon-gamma (IFN-γ) levels in AdvanSureI3 TB-IGRA and spot counts in T-SPOT.TB. Results: The IGRA findings of the two assays revealed 90.8% (95% confidence interval [CI] = 84.2-94.8) total agreement with κ of 0.740 (95% CI = 0.595-0.885), showing substantial agreement between the two tests. Additionally, the amount of IFN-γ in AdvanSureI3 TB-IGRA increased with the spot counts in T-SPOT.TB (p < 0.001). Conclusions: Our research revealed that the results of the AdvanSureI3 TB-IGRA were comparable to those of T-SPOT.TB.

Long-Term Immune Response Profiles to SARS-CoV-2 Vaccination and Infection in People with Multiple Sclerosis on Anti-CD20 Therapy

Our objective was to analyze longitudinal cellular and humoral immune responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination in people with multiple sclerosis (pwMS) on B-cell depleting treatment (BCDT) compared to pwMS without immunotherapy. We further evaluated the impact of COVID-19 infection and vaccination timing. PwMS (n = 439) on BCDT (ocrelizumab, rituximab, ofatumumab) or without immunotherapy were recruited for this prospective cohort study between June 2021 and June 2022. SARS-CoV-2 spike-specific antibodies and interferon-γ release of CD4 and CD8 T-cells upon stimulation with spike protein peptide pools were analyzed at different timepoints (after primary vaccination, 3 and 6 months after primary vaccination, after booster vaccination, 3 months after booster). Humoral response to SARS-CoV-2 was consistently lower whereas T-cell response was higher in patients with BCDT compared to controls. Cellular and humoral responses decreased over time after primary vaccination and increased again upon booster vaccination, with significantly higher antibody titers after booster than after primary vaccination in both untreated and B-cell-depleted pwMS. COVID-19 infection further led to a significant increase in SARS-CoV-2-specific responses. Despite attenuated B-cell responses, a third vaccination for patients with BCDT seems recommendable, since at least partial protection can be expected from the strong T-cell response. Moreover, our data show that an assessment of T-cell responses may be helpful in B-cell-depleted patients to evaluate the efficacy of SARS-CoV-2 vaccination.

"Spotting" Mycobacterium bovis infection in leopards (Panthera pardus) - novel application of diagnostic tools

Background

Mycobacterium bovis (M. bovis) is the causative agent of animal tuberculosis (TB) which poses a threat to many of South Africa's most iconic wildlife species, including leopards (Panthera pardus). Due to limited tests for wildlife, the development of accurate ante-mortem tests for TB diagnosis in African big cat populations is urgently required. The aim of this study was to evaluate currently available immunological assays for their ability to detect M. bovis infection in leopards.

Methods

Leopard whole blood (n=19) was stimulated using the QuantiFERON Gold Plus In-Tube System (QFT) to evaluate cytokine gene expression and protein production, along with serological assays. The GeneXpert® MTB/RIF Ultra (GXU®) qPCR assay, mycobacterial culture, and speciation by genomic regions of difference PCR, was used to confirm M. bovis infection in leopards.

Results

Mycobacterium bovis infection was confirmed in six leopards and individuals that were tuberculin skin test (TST) negative were used for comparison. The GXU® assay was positive using all available tissue homogenates (n=5) from M. bovis culture positive animals. Mycobacterium bovis culture-confirmed leopards had greater antigen-specific responses, in the QFT interferon gamma release assay, CXCL9 and CXCL10 gene expression assays, compared to TST-negative individuals. One M. bovis culture-confirmed leopard had detectable antibodies using the DPP® Vet TB assay.

Conclusion

Preliminary results demonstrated that immunoassays and TST may be potential tools to identify M. bovis-infected leopards. The GXU® assay provided rapid direct detection of infected leopards. Further studies should aim to improve TB diagnosis in wild felids, which will facilitate disease surveillance and screening.

Evaluation of the performance of the IFN-γ release assay in bovine tuberculosis free herds from five European countries

The diagnostic methods for granting and maintenance of the official tuberculosis-free (OTF) status and for intra-Community movement of cattle are the tuberculin skin tests (single or comparative) and the interferon-γ (IFN-γ) release assay (IGRA). However, until now, IGRAs have been primarily applied in infected farms in parallel to the skin test to maximize the number of infected animals detected. Therefore, an evaluation of the performance of IGRAs in OTF herds to assess whether if their specificity is equal to or higher than that of the skin tests is needed. For this, a panel of 4365 plasma samples coming from 84 OTF herds in six European regions (five countries) was assembled and analysed using two IGRA kits, the ID Screen^® Ruminant IFN-g (IDvet) and the Bovigam™ TB Kit (Bovigam). Results were evaluated using different cut-offs, and the impact of herd and animal-level factors on the probability of positivity was assessed using hierarchical Bayesian multivariable logistic regression models. The percentage of reactors ranged from 1.7 to 21.0% (IDvet: S/P ≥ 35%), and 2.1-26.3% (Bovigam: OD_bovis-OD_PBS ≥ 0.1 and OD_bovis-OD_avium ≥ 0.1) depending on the region, with Bovigam disclosing more reactors in all regions. The results suggest that specificity of IGRAs can be influenced by the production type, age and region of origin of the animals. Changes in the cut-offs could lead to specificity values above 98-99% in certain OTF populations, but no single cut-off yielding a sufficiently high specificity (equal or higher than that of skin tests) in all populations was identified. Therefore, an exploratory analysis of the baseline IFN-γ reactivity in OTF populations could help to assess the usefulness of this technique when applied for the purpose of maintaining OTF status.

QuantiFERON-TB Gold Plus Performance in Children: A Narrative Review

This review summarizes studies evaluating the performance of the QuantiFERON-TB Gold Plus (QFT-Plus) interferon-gamma release assay (IGRA) test for Mycobacterium tuberculosis ( Mtb ) infection in children. Literature searching was conducted using PubMed, MEDLINE and Embase (January 2017 to December 2021) and the terms "children" or "pediatric" and "IGRAs" or "QuantiFERON-TB Gold Plus." Selected studies (N = 14; 4646 subjects) enrolled children with Mtb infection, tuberculosis (TB) disease or healthy children with household TB contacts. Agreement between QFT-Plus and tuberculin skin test (TST) (kappa values) ranged from -0.201 (no agreement) to 0.83 (almost perfect agreement). Assay sensitivity of QFT-Plus (against reference standard of microbiologically confirmed TB disease) was 54.5%-87.3%, with no reported difference in children less than 5 versus greater than or equal to 5 years of age. In individuals less than or equal to 18 years of age, the rate of indeterminate results was 0%-33.3% (2.6% in children <2 years). IGRAs may overcome the limitations of TST in young, Bacillus Calmette-Guérin-vaccinated children.

Comparative analysis between STANDARD-E Covi-FERON ELISA with pre-existing IFN-γ release assays and determination of the optimum cutoff value for assessment of T-Cell response to SARS-CoV-2

BACKGROUND

Interferon-gamma (IFN-γ) release assays (IGRAs) are useful for the assessment of the T-cell response to severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2). We aimed to assess the performance of the newly developed IGRA ELISA test compared to the pre-existing assays and to validate the cutoff value in real-world conditions.

METHODS

We enrolled 219 participants and assessed agreement between STANDARD-E Covi-FERON ELISA with Quanti-FERON SARS-CoV-2 (QFN SARS-CoV-2), as well as with T SPOT Discovery SARS-CoV-2 based on Cohen's kappa-index. We further determined the optimal cutoff value for the Covi-FERON ELISA according to the immune response to vaccinations or infections.

RESULTS

We found a moderate agreement between Covi-FERON ELISA and QFN SARS-CoV-2 before vaccination (kappa-index = 0.71), whereas a weak agreement after the first (kappa-index = 0.40) and second vaccinations (kappa-index = 0.46). However, the analysis between Covi-FERON ELISA and T SPOT assay demonstrated a strong agreement (kappa-index >0.7). The cut-off value of the OS (original spike) marker was 0.759 IU/mL with a sensitivity of 96.3% and specificity of 78.7%, and that of the variant spike (VS) marker was 0.663 IU/mL with a sensitivity and specificity of 77.8% and 80.6%, respectively.

CONCLUSION

The newly determined cut-off value may provide an optimum value to minimize and prevent the occurrence of false-negative or false-positive during the assessment of T-cell immune response using Covi-FERON ELISA under real-world conditions.

Comparison of Two Commercially Available Interferon-γ Release Assays for T-Cell-Mediated Immunity and Evaluation of Humoral Immunity against SARS-CoV-2 in Healthcare Workers

Cellular immunity against SARS-CoV-2 is an important component of the immune response to the virus. At present, two such tests based on interferon-gamma release (interferon-γ release assays, IGRAs) are available-Quan-T-Cell SARS-CoV-2 by EUROIMMUN and T-SPOT.COVID by Oxford Immunotec. In this paper, we compared the results of these two tests in 90 subjects employed at the Public Health Institute Ostrava who had previously undergone COVID-19 infection or were vaccinated against that disease. To the best of our knowledge, this is the first head-to-head comparison of these two tests evaluating T-cell-mediated immunity against SARS-CoV-2. In addition, we also evaluated humoral immunity in the same individuals using the in-house virus neutralization test and IgG ELISA assay. The evaluation yielded similar results for both IGRAs, with Quan-T-Cell appearing to be insignificantly (p = 0.08) more sensitive (all 90 individuals were at least borderline positive) than T-SPOT.COVID (negative results found in five patients). The overall qualitative (presence/absence of immune response) agreement of both tests with virus neutralization test and anti-S IgG was also excellent (close or equal to 100% in all subgroups, with the exception of unvaccinated Omicron convalescents, a large proportion of whom, i.e., four out of six subjects, were IgG negative while at least borderline positive for T-cell-mediated immunity measured by Quan-T). This implies that the evaluation of T-cell-mediated immunity is a more sensitive indicator of immune response than the evaluation of IgG seropositivity. This is true at least for unvaccinated patients with a history of being infected only by the Omicron variant, but also likely for other groups of patients.

Performance of Interferon-γ Release Assays in Patients with Mycobacterium kansasii Infection

Objective

To evaluate the performance of interferon-γ release assays (IGRAs) in patients with Mycobacterium kansasii infection.

Methods

Consecutive patients between May 2012 and June 2021 who had positive for mycobacterial cultures and who underwent IGRAs (T-SPOT.TB or QuantiFERON-TB Gold [QFT-G]) were included in the analysis. The IGRA positivity rates among patients with M. kansasii isolates were then calculated. If M. kansasii was identified in at least two sputum samples or in sterile samples, M. kansasii disease was then diagnosed. Otherwise, colonisation was considered.

Results

During the study period, 54 patients with M. kansasii infection underwent T-SPOT.TB (n=48) or QFT-G (n=6) assays. The mean age was 44.1±13.4 years, 85.2% (46/54) were male. Eight patients were diagnosed with M. kansasii disease and another 46 patients were considered to have colonisation. Twenty-four patients (T-SPOT.TB, n=23; QFT-G, n=1) were positive for IGRAs, for an overall rate of 44.4% (24/54; T-SPOT.TB, 47.9% [23/48]; QFT-G, 16.7% [1/6]) for IGRAs, 25.0% (2/8) for M. kansasii disease, and 47.8% (22/46) for colonisation.

Conclusion

Positive IGRA rates were relatively low in patients with M. kansasii infection. More efforts are required to improve the performance of IGRAs in diagnosing M. kansasii infection.

Serial testing of latent tuberculosis infection in patients with diabetes mellitus using interferon-gamma release assay, tuberculin skin test, and creation tuberculin skin test

Background

Diabetes mellitus (DM) patients with latent tuberculosis infection (LTBI) have an increased risk of developing active tuberculosis (TB) due to impaired immunity. The performance of currently available immune response-based assays for identification of TB infection had been rarely evaluated in patients with type 2 DM (T2DM) in China.

Methods

A prospective study was conducted to investigate the status of LTBI in patients with confirmed T2DM. At the baseline survey, the prevalence of LTBI was tested using interferon-gamma release assay (IGRA), tuberculin skin test (TST) and creation tuberculin skin test (C-TST) in parallel. After a 3-month interval, the participants were retested by the three assays to estimate their performance in the serial testing.

Results

A total of 404 participants with T2DM were included in the study. At baseline, after excluding active TB, the prevalence of LTBI identified by TST (≥ 10 mm), C-TST (≥ 5 mm) and IGRA (≥ 0.35 IU/ml) were 9.65% (39/404), 10.40% (42/404) and 14.85% (60/404), respectively. The concordance of TST and C-TST results with IGRA results was 86.39% (349/404) and 92.08% (372/404) with a Kappa coefficient of 0.37 [95% confidence interval (CI): 0.24- 0.50] and 0.64 (95% CI: 0.53- 0.76), respectively. After a 3-month interval, the continuous results of TST, C-TST and IGRA were observed to be increased with testing conversion for 50, 26 and 27 patients, respectively. For TST and C-TST conversions, the distribution of their quantitative results in serial tests varied significantly when further classified by baseline IGRA dichotomous results.

Conclusion

In studied patients with T2DM, C-TST showed higher consistency with IGRA as compared to TST. The present of conversion observed in serial testing suggested that boosting effect of skin testing should be considered for identify of LTBI in patients with T2DM.

Interferon-gamma Release Assay-positive Granulomatous Interstitial Nephritis in a Patient with a History of Diffuse Large B Cell Lymphoma

Tuberculosis is a common etiology of granulomatous interstitial nephritis (GIN). However, the absence of evidence of lung involvement and lack of mycobacterial isolation in cultures make the etiological diagnosis and treatment decision challenging. We herein report a 46-year-old man with severe renal failure, a persistent fever, and a history of lymphoma. A renal biopsy exhibited GIN. Despite no evidence of tuberculosis except for a positive interferon-gamma release assay (IGRA), the patient was successfully treated with anti-tuberculosis drugs. Our case suggests that anti-tuberculosis therapy should be considered for patients with IGRA-positive GIN after excluding other etiologies.

Assessing T-Cell Immunity in Kidney Transplant Recipients with Absent Antibody Production after a 3rd Dose of the mRNA-1273 Vaccine

The vulnerable population of kidney transplant recipients (KTRs) are low responders to COVID-19 vaccines, so specific immune surveillance is needed. The interferon-gamma (IFN-γ) release assay (IGRA) is effective in assessing T cell-mediated immunity. We assessed SARS-CoV-2-directed T cell responses in KTRs with absent antibody production after a third dose of the mRNA-1273 vaccine, using two different IGRAs. A cohort of 57 KTRs, who were actively followed up, received a third dose of the mRNA-1273 vaccine. After the evaluation of humoral immunity to SARS-CoV-2, 14 seronegative patients were tested with two commercial IGRAs (SD Biosensor and Euroimmun). Out of 14 patients, one and three samples were positive by IGRAs with Euroimmun and SD Biosensor, respectively. The overall agreement between the two assays was 85.7% (κ = 0.444). In addition, multivariate linear regression analysis showed no statistically significant association between the IFN-γ concentration, and the independent variables analyzed (age, gender, years since transplant, total lymphocytes cells/mcl, CD3+ cells/mcl, CD3+ CD4+ cells/mcl, CD3+ CD8+ cells/mcl, CD19+ cells/mcl, CD3-CD16+CD56+ cells/mcl) (p > 0.01). In a vulnerable setting, assessing cellular immune response to complement the humoral response may be advantageous. Since the two commercial IGRAs showed a good agreement on negative samples, the three discordant samples highlight the need for further investigations.

Selection of the cutoff value of the tuberculin skin test for diagnosing students who need preventive treatment: A school-based cross-sectional study

Objective

Tuberculosis outbreaks in schools are common in China. This study aimed to introduce and evaluate a new screening process to help control outbreaks.

Methods

Screening information of students in three schools with tuberculosis outbreaks was collected. QuantiFERON-TB gold in-tube (QFT) results were used as the reference standard to determine the cutoff value of the tuberculin skin test (TST) for diagnosing students who need to have preventive medication.

Results

A total of 1,232 students and teachers from three different schools that all had more than three student patients with tuberculosis were included in this study. In total, 308 (25.0%) students had an induration diameter ≥10 mm; among students in a class different from the index case, the infection rate was 24.4% (264/1,084), which was lower than the rate among students in the same class (29.7%) (P = 0.157). Students in the same class as the index tuberculosis case had a much higher QFT positivity compared to those in a different class (58.1% vs. 7.7%, P < 0.0001). Diagnostic agreement between TST ≥10 mm and QFT was 36.6%. The diagnostic value reached the highest when the induration diameter of TST was ≥9 mm, with a sensitivity and specificity of 94.1% (95% CI: 89.4%–97.1%) and 27.6% (95% CI: 24.9%–30.4%), respectively. The area under the curve (AUC) was 0.664 (95% CI: 0.637–0.690, P < 0.0001).

Conclusion

In tuberculosis outbreaks in schools, if there are three or more cases of students with tuberculosis in a class or if the moderate or strong TST positivity rate is much higher than the normal range in the region, attention should be paid to those with moderately positive TST results. Interferon-gamma release assays (IGRAs) are recommended to be conducted following TST on the day of reading the results, especially among students sharing the same class with the index case. In resource-poor areas lacking IGRAs, the induration diameter of TST can be appropriately reduced from 15 to 9 mm to enhance the sensitivity of TST.

Screening of latent tuberculosis infection among patients with diabetes mellitus from a high-burden area in Brazil

Although several cohort studies have raised the important association between diabetes mellitus (DM) and latent tuberculosis infection (LTBI), evidences are limited and controversial. Furthermore, it is well documented that the poor glycemic control may exacerbate the risk for active TB. Thus, the monitoring of diabetic patients living in high-incidence areas for TB is an important concern in views of available diagnostic tests for LTBI. In this cross-sectional study, we estimate the association of DM and LTBI among diabetic patients classified as type-1 DM (T1D) or type-2 DM (T2D) living in Rio de Janeiro, RJ, Brazil - considered a high TB burden region of these country. Non-DM volunteers were included as endemic area healthy controls. All participants were screened for DM using glycosylated-hemoglobin (HbA_1c) and for LTBI using the QuantiFERON-TB Gold in Tube (QFT-GIT). Demographic, socioeconomic, clinical and laboratorial data were also assessed. Among 553 included participants, 88 (15.9%) had QFT-GIT positive test, of which 18 (20.5%) were non-DM, 30 (34.1%) T1D and 40 (45.4%) T2D. After adjustments for potential baseline confounders, age, self-reported non-white skin color and an active TB case in the family were significantly associated with LTBI among the studied population by using a hierarchical multivariate logistic regression analysis. Additionally, we verified that T2D patients were able to produce significant increased interferon-gamma (IFN-γ) plasma levels in response to Mycobacterium tuberculosis-specific antigens, when compared to non-DM individuals. Altogether, our data showed an increased prevalence of LTBI among DM patients, albeit non-statistically significant, and point out to important independent factors associated with LTBI, which deserve attention in monitoring patients with DM. Moreover, QFT-GIT test seems to be a good tool to screening LTBI in this population, even in a high TB burden area.

Changes in Interferon-Gamma Release Assay Readout after COVID-19 Vaccination: A Prospective Cohort Study

OBJECTIVES

Interferon-gamma release assays (IGRAs) are widely used in public health practice to diagnose latent tuberculosis. During the coronavirus disease (COVID-19) pandemic and rollout of COVID-19 vaccination, it has remained unclear whether COVID-19 vaccines interfere with IGRA readouts.

METHODS

We prospectively recruited healthcare workers during their annual occupational health examinations in 2021. Baseline IGRA readouts were compared with follow-up data after the participants had received two doses of COVID-19 vaccination.

RESULTS

A total of 134 baseline IGRA-negative cases (92 with ChAdOx1 vaccine, 27 with mRNA-1273 vaccine, and 15 with heterologous vaccination) and seven baseline IGRA-positive cases were analysed. Among the baseline IGRA-negative cases, there were decreased interferon-γ concentrations over the Nil (p = 0.005) and increased Mitogen-Nil (p < 0.001) values post-vaccination. For TB2-Nil value, there was a similar trend (p = 0.057) of increase observed. Compared with the 0.35 IU/mL threshold, the baseline and follow-up readout differences were less than |±0.10| IU/mL over the TB1-Nil and TB2-Nil values in >90% baseline IGRA-negative cases. No significant readout difference was observed among baseline IGRA-positive cases.

CONCLUSIONS

COVID-19 vaccination did not change IGRA interpretation in most cases. Cases showing conversion/borderline IGRA readouts should be given special consideration.

Humoral and Cellular Response after mRNA Vaccination in Nursing Homes: Influence of Age and of History of COVID-19

Background: Most residents and staff in nursing homes have received full vaccination. Factors related to the immune response to vaccination might be related to the risk of future severe COVID-19 and may guide the need for vaccine boosters. Design: Nursing homes that were tested in a point survey in July-October 2020 were again analyzed after a vaccination campaign in June-July 2021. Immune responses according to IgG against nucleocapsid and spike antigens, and CD4 and CD8 interferon-gamma release assay against spike antigens, were evaluated. Results: A total of 1973 subjects were tested (61.7% residents, 48.3% staff), with a mean (SD) follow-up of 46.4 (3.6) weeks between assessments. More than half of residents and more than a third of staff had evidence of COVID-19 before vaccination; 26.9% and 22.7% had seroreversion of IgG-N, and 8.9% and 4.6% had IgG-N seroconversion at second assessment, respectively. Up to 96.8% of residents and 98.1% of workers had positive IgG-S after a mean of 19.9 (2.1) weeks after vaccination. In residents with vs without a history of COVID-19, IgG-S titers were 4.11 (0.54) vs. 2.73 (0.74) logAU/mL (p < 0.001); in workers these titers were 3.89 (0.61) vs. 3.15 (0.64) logAU/mL (p < 0.001). Linear regression analysis showed that younger age (OR: −0.03 per 10 years-older [95% CI, −0.04 to −0.02], p < 0.001) and evidence of COVID-19 (OR: 1.14 [95% CI, 1.08 to 1.20], p < 0.001) are associated with greater IgG-S titers after vaccination. A direct association was found between IgG-S titers and the intensity of IFN-gamma response against spike antigens. Conclusions: Waning of humoral response and reinfection seems to be more frequent in older as compared to younger adults, although cellular responses shortly after vaccination are comparable between these groups. Younger age and prior COVID-19 are related to greater humoral response after vaccination against SARS-CoV-2.

Impact of Positive Interferon-Gamma Release Assay on IVF-ET Pregnancy Outcomes in Infertile Patients With Untreated Prior Tuberculosis: A Prospective Cohort Study

Introduction: Tuberculosis (TB) is a major infectious disease that seriously endangers human health and female reproduction. In our previous study, 10.4% of infertile patients preparing for In vitro fertilization and embryo transfer (IVF-ET) had prior pulmonary TB (PTB) as detected on chest X-ray (CXR) screening. Among them, 81.8% did not receive anti-TB treatment. It remains unclear whether infertile women with untreated prior PTB have latent TB infection (LTBI) and whether LTBI affects IVF-ET outcomes. In this study, we aim to analyze the relationship between LTBI and pregnancy outcomes following IVF-ET in patients with untreated prior PTB.

Methods and Analysis: We designed a prospective cohort study of 1,200 infertile women with CXR findings suggestive of old-healed untreated TB, who are preparing for IVF-ET. Patients with a history of active TB and anti-TB treatment will be excluded. Interferon-gamma release assay (IGRA) will be used in patients with CXR findings suggestive of old-healed untreated TB to construct a cohort of IGRA-positive and IGRA-negative patients. Participants will undergo IVF-ET. General information, including age, body mass index, infertility causes, and controlled ovarian hyperstimulation protocol, will be recorded. Participants will be followed up during pregnancy. The primary outcome is live birth. Secondary outcomes include the numbers of retrieved oocytes, high-quality embryo rate, clinical pregnancy, number of active TB cases during pregnancy, and miscarriage.

Ethics and Dissemination: The study was approved by the Ethics Committee of Peking University Third Hospital [approval number (2020)218-01; approval date: June 19, 2020]. The research results will be disseminated through scientific/medical conferences and published in academic journals.

Trial Registration:ClinicalTrials.gov; identifier: NCT04443283.

Performance of the T-SPOTⓇ.COVID test for detecting SARS-CoV-2-responsive T cells

OBJECTIVE

To evaluate the performance of the T-SPOT.COVID test for identifying SARS-CoV-2-responsive T-cells in participants with SARS-CoV-2 infection.

METHODS

The T-SPOT.COVID test uses ELISpot interferon-gamma release assay (IGRA) methodology to measure T cell responses to SARS-CoV-2 spike S1 and nucleocapsid peptides. T-SPOT.COVID and anti-N immunoglobulin (Ig) G serology tests were performed on blood from 186 patients with nucleic acid amplification test (NAAT)-confirmed-SARS-CoV-2 infection and 100 control group participants.

RESULTS

In the 2-8 weeks after NAAT-diagnosed SARS-CoV-2 infection, the T-SPOT.COVID test detected 98.4% (63 of 64) of infected participants, while anti-N IgG serology detected 82.8%. In the first 2 weeks after diagnosis, during adaptive immune response activation, there were less reactive T-SPOT.COVID responses (75.7%, 28 of 37 infected participants) and many less seropositive responses (32.4%). Response numbers tapered after 8 weeks; however, T-SPOT.COVID test continued to detect most participants with confirmed infection (83.6%, 56 of 67) and continued to out-perform serology (52.2%). T-SPOT.COVID response due to cross-reactive T cells was ruled out by demonstrating that, of 44 control group participants with T cells responsive to 4 human common cold coronavirus peptides, only 1 was T-SPOT.COVID reactive.

CONCLUSION

The T-SPOT.COVID test performed well in detecting SARS-CoV-2-sensitized T-cells over many months.

Patch testing versus interferon-gamma release assay in evaluation of drug eruptions

Delayed-onset T-cell-mediated cutaneous adverse drug reactions are an uncommon but potentially serious result of medication exposures. Identification of culprit medications is crucial, but clinical diagnosis is often difficult. Patch tests and interferon-gamma release assays (IFNγ-RA) were previously reported as potentially useful ancillary tests, while rechallenges remain the reference standard test. We compared the number of positive test results with patch testing and IFNγ-RA for drugs implicated as possible causes of cutaneous reactions. Fifty-one patients with a suspected cutaneous drug eruption underwent patch testing and IFNγ-RA for suspected drugs. Participants were followed up at least 9 months after the onset of the rash with results compared with the clinical diagnosis. Forty-two patients presented with morbilliform/eczematous eruptions; five were diagnosed with fixed drug eruption (FDE) and four with erythema multiforme. None had positive patch testing to the drugs tested. A total of 8/51 (15.6%) patients had positive reaction by the IFNγ-RA, and an additional 11 (21.6%) patients had borderline results. Positive or borderline results were more likely in patients with FDE (80%) than morbilliform/eczematous eruptions (30.9%) or erythema multiforme (25%). Our study emphasizes the necessity of additional effective ancillary tests in the evaluation of drug eruptions and supports the use of IFNγ-RA for drug testing as a tool for identifying medications associated with cutaneous drug eruptions.

Long-Term Course of Humoral and Cellular Immune Responses in Outpatients After SARS-CoV-2 Infection

Characterization of the naturally acquired B and T cell immune responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is important for the development of public health and vaccination strategies to manage the burden of COVID-19 disease. We conducted a prospective, cross-sectional analysis in COVID-19 recovered patients at various time points over a 10-month period in order to investigate how circulating antibody levels and interferon-gamma (IFN-γ) release by peripheral blood cells change over time following natural infection. From March 2020 till January 2021, we enrolled 412 adults mostly with mild or moderate disease course. At each study visit, subjects donated peripheral blood for testing of anti-SARS-CoV-2 IgG antibodies and IFN-γ release after SARS-CoV-2 S-protein stimulation. Anti-SARS-CoV-2 immunoglobulin G (IgG) antibodies were positive in 316 of 412 (76.7%) and borderline in 31 of 412 (7.5%) patients. Our confirmation assay for the presence of neutralizing antibodies was positive in 215 of 412 (52.2%) and borderline in 88 of 412 (21.4%) patients. Likewise, in 274 of 412 (66.5%) positive IFN-γ release and IgG antibodies were detected. With respect to time after infection, both IgG antibody levels and IFN-γ concentrations decreased by about half within 300 days. Statistically, production of IgG and IFN-γ were closely associated, but on an individual basis, we observed patients with high-antibody titres but low IFN-γ levels and vice versa. Our data suggest that immunological reaction is acquired in most individuals after natural infection with SARS-CoV-2 and is sustained in the majority of patients for at least 10 months after infection after a mild or moderate disease course. Since, so far, no robust marker for protection against COVID-19 exists, we recommend utilizing both, IgG and IFN-γ release for an individual assessment of the immunity status.

Clinical features and management of presumed ocular tuberculosis: A long-term follow-up cohort study in a tertiary referral center in Brazil

PURPOSE

To evaluate the clinical features and management of presumed ocular tuberculosis (OTB).

METHOD

A prospective 3-year follow-up study of patients with ocular inflammation that performed Interferon-gamma release assay (IGRA) and tuberculin skin test (TST) was conducted in a tertiary referral center in Brazil. Patients with clinical signs highly suspect of OTB with a positive TST and/or IGRA with other causes ruled out were prescribed anti-tuberculosis therapy (ATT) during 9 months. Clinical features and treatment outcomes were recorded.

RESULTS

Seventy-two patients (mean age 48.3 ± 15.7 years) were included in the study, and most were female (65.3%, n = 47). Posterior uveitis (43.1%, n = 31) was the main clinical feature. Multifocal choroiditis (25%, n = 18) was the most common choroidal involvement. Concomitant oral prednisone (45.8%, n = 33) during ATT was associated with more recurrences (p = 0.04). A significant difference (p < 0.001) between initial and final best-corrected visual acuity after ATT conclusion was observed. Cure or remission was observed in 58 (85.3%) patients that completed follow-up (n = 68).

CONCLUSION

In our cohort some variation in demographics and ocular phenotypes of presumed OTB was observed. The high rates of cure or remission of our patients strongly support the ATT in presumed OTB. Oral corticosteroids during ATT were associated with higher recurrences rates.

Tuberculosis in Internationally Displaced Children Resettling in Harris County, Texas, USA, 2010-20151

US guidelines have recommended testing children emigrating from high tuberculosis-incidence countries with interferon-gamma release assays (IGRAs) or tuberculin skin tests (TSTs). We describe the Harris County (Texas) Public Health Refugee Health Screening Program's testing results during 2010-2015 for children <18 years of age: 5,990 were evaluated, and 5,870 (98%) were tested. Overall, 364 (6.2%) children had >1 positive test: 143/1,842 (7.8%) were tested with TST alone, 129/3,730 (3.5%) with IGRA alone, and 92/298 (30.9%) with both TST and IGRA. Region of origin and younger age were associated with positive TST or IGRA results. All children were more likely to have positive results for TST than for IGRA (OR 2.92, 95% CI 2.37-3.59). Discordant test results were common (20%) and most often were TST+/IGRA- (95.0%), likely because of bacillus Calmette-Guérin vaccination. Finding fewer false positives supports the 2018 change in US immigration guidelines that recommends using IGRAs for recently immigrated children.

Overuse of Tuberculosis Surveillance Testing in Patients With Inflammatory Bowel Disease Compared to Non-IBD Patients on Biologic Therapy

Background

Biologic treatment for moderate to severe inflammatory bowel disease (IBD) places patients at risk for infectious complications. Tuberculosis (TB) infection and reactivation can lead to serious morbidity and mortality for immunosuppressed patients. As a result, guidelines recommend screening for TB before starting biologic treatment, but a paucity of data remains on the utility of surveillance testing.

Methods

We performed a retrospective chart review at a single academic center evaluating both IBD and non-IBD patients on biologic therapy. The primary outcome was to determine the number of subsequent surveillance tests performed after initial screening for latent TB in both patient groups.

Results

A total of 188 patients (147 IBD and 41 non-IBD patients) on biologic therapy were included. Screening for TB before biologic treatment was performed in 56% of non-IBD patients versus 83% for patients with IBD (P = 0.0003). Of the total cohort, 65% had at least 2 follow-up surveillance tests for TB. Three or more surveillance tests were performed in 40% of patients with IBD versus only 13% for non-IBD patients (P = 0.0132). A total of 7 patients (4%) had an abnormal surveillance test. No patients were confirmed to have a diagnosis of TB or underwent treatment.

Conclusions

Patients on biologic therapy unnecessarily undergo surveillance testing for TB. Patients with IBD on biologic therapy are screened annually for TB at a higher rate compared to non-IBD patients. Standardization of care among patients on biologic therapy is necessary to avoid excessive testing in areas with a low incidence of TB.

Serial Interferon-Gamma Release Assay (IGRA) Testing to Monitor Treatment Responses in Cases of Feline Mycobacteriosis

The interferon-gamma release assay (IGRA) is used to diagnose cases of feline mycobacteriosis, but the use of serial testing to monitor treatment responses has not been evaluated in this species. From a population of cats that underwent IGRA testing for diagnostic investigation, individuals were identified with a pre- and end-of-treatment IGRA that passed control thresholds. The number of cats which reverted to negative at the end-of-treatment IGRA, changes in paired antigen-specific optical density (OD) values and differences in the pre-treatment antigen-specific OD values for those which underwent reversion were compared. Factors to explain reversion or recurrence of disease post-treatment were explored. Four of 18 cats (22%) reverted to negativity at the point of clinical resolution (p = 0.33), there was no difference in paired antigen-specific OD values (p ≥ 0.12), and cats that reverted did not have a lower baseline OD value (p = 0.63). No statistically significant factors were identified to predict reversion (p ≥ 0.08). Remaining positive at the end of treatment IGRA was not associated with recurrence of disease post-treatment (p = 0.34). Overall, these data suggest there is limited value in the use of the IGRA to monitor treatment responses in cats.

Usefulness of screening tests for diagnosis of latent tuberculosis infection in children

BACKGROUND

The aim of this study is to provide a basis for the development of appropriate screening strategies and evaluate the indications of the interferon-gamma release assay (IGRA) in Bacillus Calmette-Guérin (BCG)-vaccinated children.

METHODS

Children who were examined with both IGRA (QuantiFERON®-TB Gold Plus) and tuberculin skin test (TST) for tuberculosis infection were included in the study. Underlying medical conditions of the patients were recorded. Cohen's κ was run to determine if there was an agreement between TST and IGRA.

RESULTS

A total of 220 patients with a mean age of 11.05 ± 4.43 years (2.5-18 years) were analyzed. Ninety-nine patients were immunocompromised and 121 patients were immunocompetent. TSTs and IGRA showed none to the slight agreement in both of the immunocompromised and immunocompetent patients. In the immunocompromised group, 43/99 (43.4%) and the immunocompetent group 35/121 (28.9%) of the tests did not show any correlation.

CONCLUSION

In a high-risk setting where the BCG vaccine is mandatory, it may be beneficial to use IGRA primarily in immunocompetent patients. In immunocompromised patients, the use of both the TST and IGRA could increase the efficacy of screening for latent tuberculosis infection.

Male Sex Bias in Immune Biomarkers for Tuberculosis

Males have a bias toward developing sputum smear-positive pulmonary tuberculosis, whereas other forms of the disease have an equal sex ratio. Immune responses are known to be affected by estrogen and testosterone. Biomarkers may therefore be affected by these hormones, especially between 16 and 45 years of age when the differences are most marked. Using large data sets, we examined whether the male bias was significant in terms of diagnosis or predictive ability for the development of disease in those exposed to tuberculosis. Despite the large numbers, the need to specify homogeneous population groups for analysis affected the statistical power to discount a useful biomarker. In general, males showed higher interferon-gamma responses to TB antigens ESAT-6 and CFP-10, whilst females had stronger tuberculin responses in those with sputum smear- and culture-positive tuberculosis, but smaller responses in those who were screened for tuberculosis and who did not develop disease. Importantly, in contacts of sputum smear-positive pulmonary tuberculosis, more males who did not develop tuberculosis had tuberculin skin tests in the range between 10 and 14 mm, suggesting that sex-specific cut-offs might be better than general cut-off values for determining who should receive preventive treatment. Immunocytochemistry of the tuberculin responses correlated with cell numbers only in females. Total and anti-lipoarabinomannan IgM antibody levels were lower in males, whereas total and anti-BCG IgE antibody levels were higher. Evaluation of biomarkers should take account of the spectrum of tuberculosis and male sex bias for sputum smear-positive pulmonary tuberculosis. These findings improve our understanding of how immune responses contribute to the pathogenesis of infectious tuberculosis as well as suggesting clinical applications of the differences between the sexes.

Machine Learning Algorithms Evaluate Immune Response to Novel Mycobacterium tuberculosis Antigens for Diagnosis of Tuberculosis

Rationale

Tuberculosis diagnosis in children remains challenging. Microbiological confirmation of tuberculosis disease is often lacking, and standard immunodiagnostic including the tuberculin skin test and interferon-γ release assay for tuberculosis infection has limited sensitivity. Recent research suggests that inclusion of novel Mycobacterium tuberculosis antigens has the potential to improve standard immunodiagnostic tests for tuberculosis.

Objective

To identify optimal antigen–cytokine combinations using novel Mycobacterium tuberculosis antigens and cytokine read-outs by machine learning algorithms to improve immunodiagnostic assays for tuberculosis.

Methods

A total of 80 children undergoing investigation of tuberculosis were included (15 confirmed tuberculosis disease, five unconfirmed tuberculosis disease, 28 tuberculosis infection and 32 unlikely tuberculosis). Whole blood was stimulated with 10 novel Mycobacterium tuberculosis antigens and a fusion protein of early secretory antigenic target (ESAT)-6 and culture filtrate protein (CFP) 10. Cytokines were measured using xMAP multiplex assays. Machine learning algorithms defined a discriminative classifier with performance measured using area under the receiver operating characteristics.

Measurements and main results

We found the following four antigen–cytokine pairs had a higher weight in the discriminative classifier compared to the standard ESAT-6/CFP-10-induced interferon-γ: Rv2346/47c- and Rv3614/15c-induced interferon-gamma inducible protein-10; Rv2031c-induced granulocyte-macrophage colony-stimulating factor and ESAT-6/CFP-10-induced tumor necrosis factor-α. A combination of the 10 best antigen–cytokine pairs resulted in area under the curve of 0.92 ± 0.04.

Conclusion

We exploited the use of machine learning algorithms as a key tool to evaluate large immunological datasets. This identified several antigen–cytokine pairs with the potential to improve immunodiagnostic tests for tuberculosis in children.

Frequency of Positive Conversion of Interferon-Gamma Release Assay Results Among Patients With Inflammatory Bowel Disease Treated With Non-tumor Necrosis Factor Inhibitors

Considering the risk of reactivation of latent tuberculosis infection (LTBI), not only before starting tumor necrosis factor inhibitors but also before non-TNF inhibitor therapy, LTBI screening is routinely recommended for patients with inflammatory bowel disease (IBD). However, data on the positive conversion of LTBI test results during non-TNF inhibitor therapy are scarce. Among IBD patients treated with vedolizumab and/or ustekinumab, a total of 91 patients who had negative baseline interferon-gamma release assay (IGRA) results, assessed by QuantiFERON^®-TB Gold In-tube or QuantiFERON^®-TB Gold Plus, were enrolled. Serial LTBI test results after starting non-TNF inhibitor therapy were collected, and patients' clinical characteristics were analyzed. Positive IGRA conversion was observed in six of 91 patients (6.6%). The cumulative IGRA conversion-free survival rates after starting therapy were 97.7% after 1 year and 86.7% after 2 years. Ulcerative colitis was more common among converters compared with non-converters (66.7 vs. 23.5%, P = 0.040). Among six converters, four had been treated with vedolizumab, one with ustekinumab, and the other with vedolizumab followed by ustekinumab. All six patients had been previously exposed to TNF inhibitors before non-TNF inhibitor therapy: five to infliximab and one to both infliximab and adalimumab. After positive IGRA conversion, none of the six converters developed active tuberculosis while maintaining non-TNF inhibitor therapy (median 6.8 months, range 0.4-32.1 months). Positive IGRA conversion among IBD patients treated with vedolizumab and/or ustekinumab appears to occur somewhat frequently, but its clinical implications remain to be elucidated.

Prediction of Conserved Peptides of Paracoccidioides for Interferon-γ Release Assay: The First Step in the Development of a Lab-Based Approach for Immunological Assessment during Antifungal Therapy

Impaired antigen-specific cell-mediated immunity (CMI) is a primary immunological disturbance observed in individuals that develop paracoccidioidomycosis (PCM) after exposure to Paracoccidioides spp. Restoration of Paracoccidioides-specific CMI is crucial to stop the antifungal treatment and avoid relapses. A convenient and specific laboratory tool to assess antigen specific CMI is required for the appropriate clinical treatment of fungal infections, in order to decrease the time of antifungal therapy. We used an interferon-γ release assay strategy, used in the diagnosis of latent tuberculosis infection, to address our aims in this study. Information on proteins secreted by two well-studied representative strains-Paracoccidioides brasiliensis (Pb18) and P. lutzii (Pb-01)-were explored using PubMed or MEDLINE. From 26 publications, 252 proteins were identified, of which 203 were similar according to the Basic Local Alignment Search Tool. This enabled a selection of conserved peptides using the MEGA software. The SignalP-5.0, TMHMM, IEDB, NetMHC II, and IFNepitope algorithms were used to identify appropriate epitopes. In our study, we predicted antigenic epitopes of Paracoccidioides that could bind to MHC class II and induce IFN-γ secretion. These T cell epitopes can be used in the development of a laboratory tool to monitor the CMI of patients with PCM.

Comparing the Diagnostic Performance of QuantiFERON-TB Gold Plus to Other Tests of Latent Tuberculosis Infection: A Systematic Review and Meta-analysis

BACKGROUND

We conducted a review to compare the sensitivity, specificity, reproducibility, and predictive ability of QuantiFERON-TB Gold Plus (QFT-Plus) with that of QuantiFERON-TB Gold In-Tube (QFT-GIT; QIAGEN, Hilden, Germany) and other latent tuberculosis infection (LTBI) tests.

METHODS

We searched MEDLINE, Embase, Web of Science, and the Cochrane Database of Systematic Reviews from January 2013 through May 2020. We included studies comparing QFT-Plus with at least one other LTBI test. We estimated sensitivity from studies of patients with active tuberculosis, and specificity from studies of healthy individuals with low risk of LTBI. Three independent reviewers evaluated eligibility, extracted data, and assessed risk of bias.

RESULTS

Compared with QFT-GIT, the sensitivity of QFT-Plus in patients with active TB was 1.3% higher (95% confidence interval [CI], -0.3% to 2.9%); in 2 studies of patients with very low probability of LTBI, the specificity was 0.9% lower (95% CI, -2.4% to 0.6%). These differences were not statistically significant. The agreement between QFT-Plus and QFT-GIT was high, with a pooled Cohen's kappa statistic of 0.83 (95% CI, 0.79 to 0.88). The reproducibility of QFT-GIT and QFT-Plus was similarly poor. All participants in the studies to estimate sensitivity were aged ≥15 years, and only 6 were people living with human immunodeficiency virus. We found no studies to assess predictive ability.

CONCLUSIONS

QFT-Plus has diagnostic performance that is very similar to that of QFT-GIT. Further studies are needed to assess the sensitivity of QFT-Plus in immunocompromised patients and younger children before concluding if this new version offers advantages.

Tuberculosis infection in children visiting friends and relatives in countries with high incidence of tuberculosis: A study protocol

INTRODUCTION

Tuberculosis (TB) is a global infectious disease. In low-incidence countries, paediatric TB affects mostly immigrant children and children of immigrants. We hypothesize that these children are at risk of exposure to Mycobacterium tuberculosis when they travel to the country of origin of their parents to visit friends and relatives (VFR). In this study, we aim to estimate the incidence rate and risk factors associated to latent tuberculosis infection (LTBI) and TB in VFR children.

METHODS AND ANALYSIS

A prospective study will be carried out in collaboration with 21 primary health care centres (PCC) and 5 hospitals in Catalonia, Spain. The study participants are children under 15 years of age, either immigrant themselves or born to immigrant parents, who travel to countries with high incidence of TB (≥ 40 cases/100,000 inhabitants). A sample size of 492 children was calculated. Participants will be recruited before traveling, either during a visit to a travel clinic or to their PCC, where a questionnaire including sociodemographic, epidemiological and clinical data will be completed, and a tuberculin skin test (TST) will be performed and read after 48 to 72 hours; patients with a positive TST at baseline will be excluded. A visit will be scheduled eight to twelve-weeks after their return to perform a TST and a QuantiFERON-TB Gold Plus test. The incidence rate of LTBI will be estimated per individual/month and person/year per country visited, and also by age-group.

ETHICS AND DISSEMINATION

The study protocol was approved by the Clinical Research Ethics Committee of the Hospital Universitari Mútua Terrassa (code 02/16) and the Clinical Research Ethics Committee of the Fundació Institut Universitari per a la Recerca a l'Atenció Primària de Salut Jordi Gol i Gurina (code P16/094). Articles will be published in indexed scientific journals.

TRIAL REGISTRATION

Clinical-Trials.gov: NCT04236765.

Foreign background and older age of children were associated with infection in Swedish tuberculosis contacts

AIM

We present our results using interferon-gamma release assays in any child <18 years or tuberculin skin tests in Bacille Calmette-Guérin unvaccinated children for tuberculosis contact investigation in Stockholm, Sweden.

METHODS

During 2000-2019, we investigated 892 children with a median age of seven years. We explored associations between TB infection and characteristics such as closeness to contact, age, sex, BCG status and foreign origin.

RESULTS

The overall rates were for TB infection 10.2% (n = 91) and for TB disease 1.1% (n = 10). In addition to infectiousness of index case and closeness of contact, foreign background, male sex and increasing age were independently associated with infection. In foreign-born children, the rates of tuberculosis infection and disease were 18.7% and 3.9%, respectively. In 18/46 (39%) infected foreign-born children, a baseline negative tuberculosis test supported a diagnosis of recent infection.

CONCLUSION

Foreign background, older age and male sex were associated with infection. In a significant proportion of infected children, a previous negative test made recent infection likely.

Diagnostic Accuracy of QuantiFERON-TB Gold Plus Assays in Children and Adolescents with Tuberculosis Disease

In 2016, a new interferon-gamma release assay, QuantiFERON-TB Gold Plus, was introduced. We conducted a cross-sectional multicenter study, involving 158 children and adolescents with tuberculosis disease. The overall sensitivity of the assay was 82.9% (IQR 77.0%-88.8%), indicating that in children this test does not have higher sensitivity than previous generation interferon-gamma release assays.

Positivity of interferon-gamma release assay among foreign-born individuals, Tokyo, Japan, 2015-2017

Background

The aim of this study is to analyze interferon-gamma release assay (IGRA) data of foreign-born individuals in Japan derived from tuberculosis (TB) contact investigations.

Methods

A contact with a TB patient was considered to have occurred when an individual had contact with a TB patient for more than 8 h indoors. This is a retrospective cohort study, and all the TB contacts tested with IGRA during the contact investigations conducted by the Shinjuku city Health Office from 2015 through 2017 were enrolled.

Results

A total of 880 foreign-born contacts were investigated. The IGRA positivity of the contacts from China and Viet Nam were both 5.1% (95% confidence intervals [CIs]: 3.2%-7.8% and 2.4%-9.5%, respectively), whereas that from Nepal and Myanmar were 24.4% (95% CI: 16.0%-34.6%) and 23.3% (95% CI: 9.9%-42.3%), respectively. Multiple logistic regression analysis showed that the risk factors were smear status of the index patient (1+: adjusted odds ratio [aOR]: 6.2, 95% CI: 1.2-30.5, smear status 3+: aOR: 14.3, 95% CI: 1.7-118.2), age of the contact (aOR: 1.1, 95% CI: 1.0-1.1 for 1 year increment), and being born in Nepal (aOR: 5.6, 95% CI: 2.8-11.2) and Myanmar (aOR: 4.3, 95% CI: 1.4-13.0), compared with China as reference.

Conclusions

In contact investigations involving foreign-born individuals, local health offices should carefully consider the composition of the TB contacts and expand the focus of the investigation, if deemed necessary.

Implementation of routine interferon-gamma release assay testing in a South London HIV cohort

Human immunodeficiency virus (HIV) infection is a major risk factor for the development of tuberculosis (TB). Although guidelines recommend that people with HIV from high TB incidence countries and those with risk factors are screened for latent TB infection (LTBI) using interferon-gamma release assays (IGRAs), this has not been widely implemented in the UK. We introduced universal LTBI screening using IGRAs at nurse-led induction clinics for patients newly presenting, transferring or re-presenting for HIV care and conducted a prospective audit from 1 January 2018 to 30 June 2019 to identify operational challenges as well as opportunities for TB prevention. Of the 223 patients, 17 had active or previously treated TB. Of the remaining 206 individuals who were eligible for IGRA testing, 78 (38%) were not tested due to logistical issues, failure to request the test or no induction visit taking place. Of the 128 (62%) individuals who were tested for LTBI, 3 (2.3%) had a positive IGRA, 4 (3.1%) an indeterminate result and 121 (94.5%) a negative result. All seven with positive/indeterminate tests were of African/Caribbean background, had CD4 cell counts >200 cells/mm3 and HIV RNA <400 copies/ml. Our audit suggests that universal LTBI screening was logistically challenging and provided few opportunities for TB prevention.

Mycobacterium bovis Infection in African Wild Dogs, Kruger National Park, South Africa

We screened African wild dogs (Lycaon pictus) in Kruger National Park, South Africa, for Mycobacterium bovis infection using an interferon-gamma release assay. We detected M. bovis sensitization in 20 of 21 packs; overall apparent infection prevalence was 83%. These animals experience high infection pressure, which may affect long-term survival and conservation strategies.

The Levels of Interferon-gamma Release as a Biomarker for Non-small-cell Lung Cancer Patients Receiving Immune Checkpoint Inhibitors

BACKGROUND/AIM

The present study aimed to prospectively examine the usefulness of interferon-gamma (IFN-γ) release (IGR) as a biomarker in non-small-cell lung cancer patients receiving immune checkpoint inhibitor treatment (ICI-Tx).

PATIENTS AND METHODS

IGR was measured using enzyme-linked immunosorbent assay at four time points: within 14 days before ICI-Tx (T1), and 8±3 (T2), 22±7 (T3), and 43±7 (T4) days after ICI-Tx.

RESULTS

Twenty-nine patients were divided into three groups based on IFN-γ levels in the IGR-positive control: Group-1 (n=8) with <10 IU/ml at T1, Group-2 (n=12) with a decrease in IFN-γ levels to <10 IU/ml at T3 and/or T4, and Group-3 (n=9) without changes in IFN-γ levels. Early progression and ICI-induced interstitial pneumonitis were frequently observed in Group-1 and Group-2, respectively. Group-3 exhibited more treatment cycles than the other groups. All three groups showed clear differences in clinical outcomes.

CONCLUSION

IFN-γ levels could be a biomarker for ICI-Tx.

Effect of diabetes mellitus on risk of latent TB infection in a high TB incidence area: a community-based study in Taiwan

OBJECTIVE

To investigate the association between diabetes and latent tuberculosis infections (LTBI) in high TB incidence areas.

DESIGN

Community-based comparison study.

SETTING

Outpatient diabetes clinics at 4 hospitals and 13 health centres in urban and rural townships. A community-based screening programme was used to recruit non-diabetic participants.

PARTICIPANTS

A total of 2948 patients with diabetes aged older than 40 years were recruited, and 453 non-diabetic participants from the community were enrolled.

PRIMARY AND SECONDARY OUTCOME MEASURES

The interferon-gamma release assay (IGRA) and the tuberculin skin test were used to detect LTBI. The IGRA result was used as a surrogate of LTBI in logistic regression analysis.

RESULTS

Diabetes was significantly associated with LTBI (adjusted OR (aOR)=1.59; 95% CI 1.11 to 2.28) and age correlated positively with LTBI. Many subjects with diabetes also had additional risk factors (current smokers (aOR=1.28; 95% CI 0.95 to 1.71), comorbid chronic kidney disease (aOR=1.26; 95% CI 1.03 to 1.55) and history of TB (aOR=2.08; 95% CI 1.19 to 3.63)). The presence of BCG scar was protective (aOR=0.66; 95% CI 0.51 to 0.85). Duration of diabetes and poor glycaemic control were unrelated to the risk of LTBI.

CONCLUSION

There was a moderately increased risk of LTBI in patients with diabetes from this high TB incidence area. This finding suggests LTBI screening for the diabetics be combined with other risk factors and comorbidities of TB to better identify high-risk groups and improve the efficacy of targeted screening for LTBI.

Modeling the Accuracy of Two in-vitro Bovine Tuberculosis Tests Using a Bayesian Approach

Accuracy of new or alternative diagnostic tests is typically estimated in relation to a well-standardized reference test referred to as a gold standard. However, for bovine tuberculosis (bTB), a chronic disease of cattle, affecting animal and public health, no reliable gold standard is available. In this context, latent-class models implemented using a Bayesian approach can help to assess the accuracy of diagnostic tests incorporating previous knowledge on test performance and disease prevalence. In Uruguay, bTB-prevalence has increased in the past decades partially because of the limited accuracy of the diagnostic strategy in place, based on intradermal testing (caudal fold test, CFT, for screening and comparative cervical test, CCT, for confirmation) and slaughter of reactors. Here, we evaluated the performance of two alternative bTB-diagnostic tools, the interferon-gamma assay, IGRA, and the enzyme-linked immunosorbent assay (ELISA), which had never been used in Uruguay in the absence of a gold standard. In order to do so animals from two heavily infected dairy herds and tested with CFT-CCT were also analyzed with the IGRA using two antigens (study 1) and the ELISA (study 2). The accuracy of the IGRA and ELISA was assessed fitting two latent-class models: a two test-one population model (LCA-a) based on the analysis of CFT/CFT-CCT test results and one in-vitro test (IGRA/ELISA), and a one test-one population model (LCA-b) using the IGRA or ELISA information in which the prevalence was modeled using information from the skin tests. Posterior estimates for model LCA-a suggested that IGRA was as sensitive (75-78%) as the CFT and more sensitive than the serial use of CFT-CCT. Its specificity (90-96%) was superior to the one for the CFT and equivalent to the use of CFT-CCT. Estimates from LCA-b models consistently yielded lower posterior Se estimates for the IGRA but similar results for its Sp. Estimates for the Se (52% 95%PPI:44.41-71.28) and the Sp (92% 95%PPI:78.63-98.76) of the ELISA were however similar regardless of the model used. These results suggest that the incorporation of IGRA for detection of bTB in highly infected herds could be a useful tool to improve the sensitivity of the bTB-control in Uruguay.

Latent tuberculosis may be missed by current screening practices: Analysis of interferon-gamma release assay results from a paediatric refugee clinic

AIMS

(i) To determine the prevalence of latent tuberculosis infection (LTBI) and characteristics associated with LTBI in children attending a paediatric refugee clinic and (ii) to determine whether current New South Wales (NSW) Health screening practices could miss LTBI cases.

METHODS

This was a retrospective analysis of tuberculosis (TB) screening data from refugee and asylum seeker children who attended a refugee clinic in a tertiary children's hospital during 2014 and 2015. We determined associations between LTBI and child characteristics at 5% significance levels.

RESULTS

Of 358 children attending the clinic, 235 children (66%) received interferon-gamma release assay (IGRA) testing, of whom 28 (11.9%) had positive results. Of the 28 with positive IGRAs, 12 (42.9%) would have been missed using NSW Health screening guidelines: two because they were younger than 2 years old, one who was born in Australia and 10 because they were not born in high TB incidence countries. IGRA results were not significantly associated with any of the child characteristics examined, including age, gender, travel through transit countries, boat versus plane arrival into Australia, whether the child had been in a detention centre or TB incidence in the source country.

CONCLUSIONS

We identified 12 children with LTBI who would have been missed using current NSW Health Department screening practices. These children are at risk of progression to active disease, particularly the two aged younger than 2 years old. We recommend universal screening.

Screening for Latent Tuberculosis in Children With Immune-mediated Inflammatory Diseases Treated With Anti-tumor Necrosis Factor Therapy: Comparison of Tuberculin Skin and T-SPOT Tuberculosis Tests

Objectives

This study aims to analyze the coherence between T-SPOT tuberculosis test (T-SPOT.TB) and tuberculin skin test (TST) with different cut-off values in screening latent tuberculosis infection (LTBI) both prior to and at the sixth month of anti-tumor necrosis factor (anti-TNF) treatment.

Patients and methods

This prospective multicentric study included 57 children (34 girls, 23 boys, mean age 12.4±3.9 years; range, 6 to 18 years) diagnosed with immune-mediated inflammatory diseases (IMIDs) evaluated with TST and T-SPOT.TB for screening LTBI both prior to and at the sixth month of treatment with anti-TNF agents. Coherence between two tests was analyzed for TST cut-off values suggested by the local guidelines and also for different possible cut-off values of TST.

Results

Tuberculin skin test was positive (≥5 mm) in 28.1% (n=16) of patients in the screening prior to treatment and in 33.3% (n=19) at the sixth month of treatment. T-SPOT.TB test was positive in 8.8% (n=5) of patients both prior to and at the sixth month of treatment. Coherence between two tests was poor or fair when compared with all possible TST cut-off values both prior to and at the sixth month of anti-TNF therapy.

Conclusion

Our results show poor coherence between T-SPOT.TB and TST for all possible cut-off values of TST. Thus, using both tests would be beneficial in screening LTBI until further studies bring new evidence on the subject.

The Application of T.SPOT-TB Assay for Early Diagnosis of Active Tuberculosis in Chronic Kidney Disease Patients Receiving Immunosuppressive Treatment

Background: The current study investigated the clinical application of the T-SPOT.TB assay for detecting tuberculosis (TB) infection in chronic kidney disease patients treated with immunosuppressive therapy. Methods: Clinical data from 91 patients were retrospectively analyzed. The rate of positive T-SPOT.TB results and spot numbers were compared before and after treatment. Clinical characteristics that may affect the test results were also investigated. Results: Two active TB cases were observed after immunosuppressive treatment, and eight patients with negative T-SPOT.TB results at baseline had positive results after treatment. No significant changes in spot numbers were observed for patients who were positive at baseline. Compared with pretreatment baseline, patients who received medium/high doses of corticosteroids had a greater number of T-SPOT.TB positive results (p = 0.016) and CFP-10 spots (p = 0.041) after treatment. For patients who received combination therapy with medium/high doses of corticosteroids, the T-SPOT.TB positive rate (p = 0.046) and CFP-10 spot number (p = 0.041) were increased after treatment, with no significant changes in the total number of spots or ESAT-6 spots. For those who received combination therapy with low doses of corticosteroids and those who received single immunosuppressive medication, there were no significant differences in the T-SPOT.TB positive rate, total spot number, or numbers of ESAT-6 and CFP-10 spots. Conclusion: The increase in positive T-SPOT.TB results was mainly associated with medium/high doses of glucocorticoids. The active TB cases might represent new infections. Regular monitoring using the T-SPOT.TB assay will help in the early detection of active TB.

Current Practices in Ocular Tuberculosis: A Survey of Brazilian Specialists

Purpose: To describe the approach of Brazilian specialists in the diagnosis and treatment of tuberculosis-associated uveitis (TBU).Methods: Members of the Brazilian Uveitis Society received an electronic invitation to participate in an online questionnaire.Results: Of the 169 invited specialists, 78 answered the questionnaire. Specialists evaluated 5.6 patients with TBU annually. Tuberculin skin test (TST, 81%) was primarily used for diagnosis. Patients with presumed TBU should always be tested for syphilis and HIV according to 51 (88%) and 47 (81%) of respondents, respectively. Chest computed tomography (CT, 72%) was preferable to chest radiography (CXR) for diagnosis. A positive TST (81%) and CXR (60%) were the main indicators of anti-tuberculous therapy, with 34%, 39%, and 14% of specialists treating for 6, 9, and 12 months, respectively.Conclusions: TST remains the preferred method for TBU diagnosis and prompt treatment by Brazilian specialists, though there is no consensus regarding disease treatment and management.